On the Roll-Off of the Activation Energy Plot in High-Temperature Flash Memory Retention Tests and its Impact on the Reliability Assessment

Abstract

In this letter, we discuss the experimental behavior of high-kappa interpoly dielectrics in floating gate memory devices with respect to the activation energy plot. It is shown that the Arrhenius extrapolation may overestimate the ten-year lifetime predictions. However, a clear correlation between the activation energy plot and the trap levels in the interpoly dielectric can be established, based on theoretical grounds. It is shown that a single-trap level typically follows an 1/T law, while a roll-off of the activation energy plot suggests the existence of various trap levels in the interpoly dielectrics. These findings have practical implications on the high-temperature retention testing methodology of novel nonvolatile memory with high-kappa interpoly dielectrics.